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1899: What book did Rachel Carson write in 1962 ? 1. Rachel Carson 's 1962 book Silent Spring said dieldrin causes mania. 2. It could almost be said that what we call the environmental movement did begin with a single book : Rachel Carson 's Silent Spring. 3. That caused Rachel Carson to write in her 1962 book Silent Spring that their disappearance might make it necessary for us to find a new national emblem. 4. 1962 : Rachel Carson writes Silent Spring, the first shot in the war against environmental pollution, particularly DDT. 6. In 1962, former U.S. Fish and Wildlife Service biologist Rachel Carson shocked the nation with her landmark book, Silent Spring. 7. In a forward to the new book, U.S. Vice-President Albert Gore described the book critically important and compared it with Silent Spring, Rachel Carson 's 1962 book that set off a movement to ban DDT and other pesticides. ……

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Maximum Entropy Formulation I Given a set of answer candidates Model the probability Define Features Functions Decision Rule

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Maximum Entropy Formulation II Given a set of answer candidates Model the probability Define Features Functions Decision Rule

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Some Considerations Model I Model I  Judge whether each candidate is a correct answer  √ Can find more than one correct answer in a sentence  ? Is the probability comparable ?  × Suffer from the unbalanced data set (1Pos / >20Neg) Model II  Find the best answer among the candidates  × In a sentence, it just find one correct answer  √ Directly make the probabilities of the candidates comparable Experiment Experiment  Model II outperform Model I by about 5%

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Features – TWord Relation for WHAT I TWord is a hypernym of answer TWord is a hypernym of answer TWord is the head of answer TWord is the head of answer Q: What is the name of the airport in Dallas Ft. Worth ? A: Wednesday morning, the low temperature at the Dallas-Fort Worth International Airport was 81 degrees. Q: What city is Disneyland in ? A: Not bad for a struggling actor who was working at Tokyo Disneyland just a few years ago.

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Features – TWord Relation for WHAT II TWord is the Appositive of answer TWord is the Appositive of answer Feature Function Feature Function  QWord = what & TWord is hypernym of answer candidate  … Q: What book did Rachel Carson write in 1962 ? A1: In her 1962 book Silent Spring, Rachel Carson, a marine biologist, chronicled DDT 's poisonous effects, …. A2: In 1962, former U.S. Fish and Wildlife Service biologist Rachel Carson shocked the nation with her landmark book, Silent Spring.

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Features – Tword Relation for HOW How many / much + NN … How many / much + NN … How long / far / tall / fast … How long / far / tall / fast …  How long …  year / day / month / …  How tall …  feet / inch / mile / …  How fast …  per day / per hour / …  Use some trigger word features Q: How many time zones are there in the world ? A: The world is divided into 24 time zones.

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Features – Subject Word Relations I Q: Who invented the paper clip ? S1: The paper clip, weighing a desk-crushing 1320 pounds, is a faithful copy of Norwegian Johan Vaaler ‘s 1899 invention, said … S2: “ Like the guy who invented the safety pin, or the guy who invented the paper clip “, David says. ×

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Features – Subject Word Relations II Match subject word in the answer sentence Match subject word in the answer sentence  Minimal Edit Distance Dependency Relationship Matching Dependency Relationship Matching  Observation – answer are close to SWord in Dependency Tree  answer and SWord have some relation  Answer candidate is a subject word  Answer candidate is the parent / child / brother of SWord  The path from the answer candidate to SWord Q: What is the name of the airport in Dallas Ft. Worth ? A: Wednesday morning, the low temperature at the Dallas-Fort Worth International Airport was 81 degrees

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Error Analysis – I Target Word Concept Unresolved Target Word Concept Unresolved  Q: What is the traditional dish served at Wimbledon? √ A: And she said she wasn't wild about Wimbledon 's famed strawberries and cream. ×A: And she said she wasn't wild about Wimbledon 's famed strawberries and cream. Choosing the Wrong Entity Choosing the Wrong Entity  Q: What actress has received the most Oscar nominations? √ A: Oscar perennial Meryl Streep is up for best actress for the film, tying Katharine Hepburn for most acting nominations with 12. ×A: Oscar perennial Meryl Streep is up for best actress for the film, tying Katharine Hepburn for most acting nominations with 12.

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Error Analysis – II Answer Candidate Granularity Answer Candidate Granularity  Q: What city is Disneyland in? √ A: Not bad for a struggling actor who was working at Tokyo Disneyland just a few years ago. ×A: Not bad for a struggling actor who was working at Tokyo Disneyland just a few years ago. Repeated Target Word in Answer Repeated Target Word in Answer  Q: How many grams in an ounce? √ A: NOTE : 30 grams is about 1 ounce. ×A: NOTE : 30 grams is about 1 ounce. Misc. Misc.

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Future Work Extract answer from Web Evaluate on other data sets  Knowledge Master Corpus How to deal with NIL question ? Incorporate more linguistic-motivated features